Filter circuitry is used in communication systems that employ multiple antennas. In general, a communication system may have a transmit path and a receive path. The transmit path extends to a first antenna port and is configured to present signals for transmission in a first communication band and a second communication band to the first antenna port for transmission via a first antenna that is coupled to the first antenna port. The receive path extends to a second antenna port and comprises a first multiple passband/multiple stopband filter that provides a plurality of passbands and a plurality of stopbands interleaved with one another, wherein a first stopband and a second stopband of the plurality of stopbands correspond respectively to the first communication band and the second communication band and are separated by a first passband of the plurality of passbands.

Filter circuitry is used in communication systems that employ multiple antennas. In general, a communication system may have a transmit path and a receive path. The transmit path extends to a first antenna port and is configured to present signals for transmission in a first communication band and a second communication band to the first antenna port for transmission via a first antenna that is coupled to the first antenna port. The receive path extends to a second antenna port and comprises a first multiple passband/multiple stopband filter that provides a plurality of passbands and a plurality of stopbands interleaved with one another, wherein a first stopband and a second stopband of the plurality of stopbands correspond respectively to the first communication band and the second communication band and are separated by a first passband of the plurality of passbands.

An antenna apparatus includes: an antenna radiator, at least one antenna cable trough, a feedpoint, and at least one first protruding metal strip; where the at least one antenna cable trough is disposed on the antenna radiator; the at least one antenna cable trough extends along a top edge to a bottom edge of the antenna radiator; the feedpoint is further disposed on the antenna radiator, and the feedpoint is disposed at an end of the bottom edge of the antenna radiator and is near a side edge of the antenna radiator; and the at least one first protruding metal strip is inserted in the antenna cable trough and is separated from the antenna radiator.

An antenna apparatus includes: an antenna radiator, at least one antenna cable trough, a feedpoint, and at least one first protruding metal strip; where the at least one antenna cable trough is disposed on the antenna radiator; the at least one antenna cable trough extends along a top edge to a bottom edge of the antenna radiator; the feedpoint is further disposed on the antenna radiator, and the feedpoint is disposed at an end of the bottom edge of the antenna radiator and is near a side edge of the antenna radiator; and the at least one first protruding metal strip is inserted in the antenna cable trough and is separated from the antenna radiator.

A high-frequency filter includes a first output to output a first signal, a first filter, a second filter, and a first matching circuit connected to an output of the first filter and to an output of the second filter. The first signal is provided to the first output from one of the output of the first filter and the output of the second filter via the first matching circuit. The first matching circuit includes a resonator connected in series between the first output and the output of only one of the first filter and the second filter.

A high-frequency filter includes a first output to output a first signal, a first filter, a second filter, and a first matching circuit connected to an output of the first filter and to an output of the second filter. The first signal is provided to the first output from one of the output of the first filter and the output of the second filter via the first matching circuit. The first matching circuit includes a resonator connected in series between the first output and the output of only one of the first filter and the second filter.

Techniques for tuning a crossed-field antenna are provided. An example of an antenna system includes a D-plate with a D-plate feed conductor, such that the D-plate is a horizontal conductor raised above and insulated from a ground plane, an E-cylinder with an E-cylinder feed conductor, such that the E-cylinder is a vertical hollow conductive cylinder of smaller diameter than the D-plate, which is mounted concentrically above and insulated from the D-plate, a transmitter tuning circuit configured to receive a signal from a transmitter, an E-cylinder tuning circuit operably coupled to the transmitter tuning circuit and the E-cylinder feed conductor, and a D-plate tuning circuit operably coupled to the transmitter tuning circuit and the D-plate feed conductor.

An antenna enables compact and robust multiband operation of portable radios. According to some embodiments, the antenna includes: a first rolled conductive strip having a first section with overlap between successive turns of the first conductive strip and a second section with no overlap between successive turns of the first conductive strip, the first section having an insulating layer between the overlapping successive turns of the first conductive strip; a second rolled conductive strip; and a flexible sheet to which both the first conductive strip and the second conductive strip are bonded.

A Near field communication (NFC) antenna and circuit modules are provided for communication terminal devices with metal frame, which aims at simplifying the implementation of the NFC antenna, and especially facilitating the application of the NFC for the devices with rear metal housing. The rear metal housing of a terminal device may be divided into three sections by the gap, the first section is metal frame, the second section is metal back shell. The metal frame as the main NFC antenna radiator, and also can be used as other microwave frequency antenna radiator. The rear metal shell connected to the motherboard ground. The NFC circuit module can transmit the NFC signal to the metal frame through different feeding methods to realize the radiation function of the NFC antenna.

An antenna tuning assembly is disclosed, including: a substrate; an input path on the substrate, for receiving control signals; a tuning network on the substrate, including an impedance circuit with a tunable impedance and at least one tuner connecting with the impedance circuit and the input path for generating an corresponding impedance in response to the control signals; an output path connecting with the tuning network on the substrate, for coupling to an external antenna according to the corresponding impedance.